Microscope for the examination of surfaces



March 17, 1936. HAUSER 2,034,096

MICROSCOPE FOR THE EXAMINATION OF" SURFACES Filed March 9, 1935 In venior:

Patented Mar. 17, 1936 UNITED STATES MICROSCOPE FOR THE EXAMINATION OF SURFACES Friedrich Hauser, Jena, Germany, assignor to the firm Carl Zeisa, Jena, Ge

rmany Application March 9, 1935, Serial No.10,244

In Germany March 16, 1934 4 Claims. (01. 88-39) The invention for which I ve filed an application in-Germany March 6, 1934 concerns a microscope for the examination .ofsurfaces, for instance worked metal surfaces, the examination consisting in comparing the microscopically en-' larged image of the surface to be examined to a standard surface represented on an enlarged scale by the image layer of a diapositive. The examination can be effected by means of a microscopein 19 which, according to the invention, the diapositive is so disposed in the image plane of the microscope obiective that it covers part of the hold of view seenin the microscope eye-piece and that, as a consequence, the standard surface is visible 1 in the field of view of the microscope, next to the surface to be examined. When the magnifi s.

cation of the image of the standard surfaceis adapted to the magnification of the image ofthe surface under examination, which is effected by the microscope objective, the said two surfaces can be readily compared to each other for instance as regards the qualities of the working.

It hasproved to be especially suitable to provide a common source of light for the illumination of both the object to be examined and thediapositive. The source of light is generally an nation of the 'diapositive. When the light rays emanating from this secondary source of light are made to strike the diapositive direct, this diapositive is not illuminated very favorably on ac- 40 count of the pencil of light rays striking it being diverged. Many of these diverged rays cannot be received by the microscope eye-piece and are therefore-lost. For this reason, it is advantageous to image the secondary source of light ap- 5 proximately in the microscope eye-piece bymeans of a condenser system disposed in front of the diapositive in the path of the illumination rays.

The illumination of the diapositive is thus made to correspond to the usual illumination of thesoobject in an apparatus for diascopic projection.

The dirrositive lies in a convergent pencil of illumination rays which substantially traverse the exit of the microscope eye-piece and can thereforeenter the observers eye at the eye-piece.

55 A favorable: illumination of the diapositive be obtained also by disposing a diflusing'filter in front of the diapositive in the path of the illumination rays. The illumination rays emanating from the secondary source of light and striking the said filter are diffused, the observer at the eye-piece of the microscope seeing the diaposltiv on a uniformly illuminated background.

e accompanying drawing represents two constructional examples of the invention. Figure 1 shows the first constructional example in central elevational section, and-Figure 2 schematically illustrates the second constructional example in a corresponding position.

- The first constructional example (Figure 1) has a microscope tube l in which a microscope 15 objective 2 and an adjustable microscope eyepiece 3 are disposed in the usual manner. The image plane of the objective 2 and-thearea of 'the field of view are de ermined by a diaphragm 4;

Into a slot 5, which e tends over half the circum- 2o ference of the tube I, a diapos'itive, whose image layer represents a standard surface on an enlarged scale, is so introduced that this image layer lies in the plane determined by the diaphragm 4. Below the diapositive'fi, a'separating wall. 1 Q

divides the tube I into an observation and an illumination chamber. The tube I is-provided with a lateralarm 8, whichholds a lamp housing Y ii inclined relatively to the axis of the microscope objective 2. In the lamp housing 9, .whose side facing the tube I has a window i0, is dis- 'of the housing 9 is covered by -a converging lens 1 l2. In that wall of the tube I which is in front of the window I0 is mounted a converging lens l3. Behind this lens l3, in the illumination cham her, is provided an inclined reflector |4. Above this reflector I4 is a-diaphragm l5, and the upper end of the illumination chamber is covered by a 40 frosted glass disc I6.

When using the microscope, the glow-lamp II is connected to a source of current and displaced in the housing 9 until the image of the incandescent filament of the lamp II, which is produced by the lens I2, is approximately concentric to the opticalaxis of the microscope objective 2. The-microscope is now so placed above a surface I! to be examined'thatr this surface intersects the axis of the microscope'objective 2 at right angles at the locus of the image of the incandescent filament. The objective 2 produces a in the plane of the diaphragm 4 an image of the surface II. The lens I3 is given such a focal length that the incandescent filament of the g lamp II is imaged by this lens II and therefiector ll in the aperture of the diaphragm Ii, the light rays that emanate from the glow-lamp ll traversing the window Ill. The illuminated aperture of the diaphragm I5 represents the secondary source of light, and'the rays emanating from this aperture illuminate the entire surface of the frosted glass disc I 6. An observer looking through the eye-piece 3 sees on the frosted glass disc it, which represents a light background, the diapositive 6 next to the image of the surface l'l to be examined, which lies in the plane of the diaphragm 4. Accordingly, the surface 11 can be compared to the standard surface in an extremely simple manner.

The second constructional example (Figure 2) differs from the first constructional example only by the different construction of-vits optical members eflecting the illumination ofthe diapositive 6. As in the first example, the rays emitted by the source of light H are combined by means of a converging lens l3 and an inclined reflector M, to an image of the source of light in the aperture of an iris diaphragm IS, in which case, however, the one half of the imaging ray pencil is stopped down by a diaphragm 19' disposed in front of the iris diaphragm l8. Ac-

cordingly, =the secondar'y'source of light in the illuminated aperture of the iris diaphragm I8 is semicircular. The illumination rays emitted by this secondary source of light represent a divergingray pencil and are directed by means of tworefiectors 20 and 2| to half a condenser lens 22 disposed in front of the diapositive 6 in the ,path of the illumination rays. The illumination rays are combined by the said lens 22 to an image of the source of light, which lies approximately in the exit pupil of'the microscope eyepiece 3, and the converging rays traverse the diapositive 6 andilluminate the image layer of this steam eflected by means of a microscope constructed according to the first constructional example. I claim:

1. A microscope for the examination of surfaces, consisting of a housing, at least one microscope objective, a microscope eye-piece, a diaposi-' tive so disposed in the said housing as to cover approximately half the microscopic image field,

a source of light, an optical system for illuminating the said diaposltive, and an optical system for illuminating the surface to be examined.

2. A microscope for the examination of surfaces, consisting of a housing, at least one mi-' croscope objective, a microscope eye-piece, 8. dia-- positive, so disposed in the said housing as to cover approximately half the microscopic image field, a source of light, an optical system for illuminating the said diapositive, a diaphragm disposed between said diapositive, the said optical system imagin the said source of light on the said diaphragm, and an optical system for illuminating the surface to be'examined. I

3. In a microscope according to claim 2, a diffusing filter disposed between the said diaphragm and the said diapositive.

4. In a microscope according 'to claim'2, a condenser system so disposed in the path of illumination rays and in front of the said diapositive that the said diaphragm is imaged by the said optical system and the.

this condenser system approximately in the light exit aperture of the-said eye-piece.

FRIEDRICH HAUSER. 40 

